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Conductive Microstructured Catalysts for the Intensification of Energy-related Chemical Processes

June 5, 2020 from 9:00 am10:00 am

Zoom Webinar with Enrico Tronconi
Department of Energy
Politecnico di Milano, Italy

Abstract

Although it is widely recognized that spatially structured catalysts/reactors are at the heart of process intensification, the engineering of the heat management in structured reactors has not received great attention until recently. There is potential, however, for significant enhancement of the radial heat transfer rates in technical multitubular packed-bed catalytic reactors with external cooling if the random packings of catalyst pellets are replaced by structured catalysts with thermally connected, highly conductive substrates [1]. This webinar will review past and recent related work from our group addressing different substrate technologies (honeycombs, open-cell foams, 3D printed cellular structures), and demonstrating their application to key processes for the production of energy vectors.

After briefly summarizing early modelling and lab-scale experimental studies, the first part of the presentation will introduce two proof-of-concept demonstrations of conductive monolith catalysts at the pilot reactor scale, namely i) a campaign of o-xylene oxidation runs (c/o Lonza Polynt, Italy) in an industrial single-tube pilot reactor (i.d. = 24.6 mm, L = 1.6 m) loaded with washcoated (V2O5/TiO2) Al honeycombs (Corning Inc., USA) operated at typical conditions for phthalic anhydride production [2], and ii) the application of conductive monolithic reactors to the Fischer-Tropsch synthesis (FTS), within a collaboration with the Eni group, during an extensive experimental campaign (over 1300 h) in a 1 m long pilot tubular reactor located at an Eni R&D facility, loaded with Co/Al2O3 catalyst particles packed in extruded Al honeycombs [3-4]. Such results clearly prove at a representative scale that highly conductive monolithic internals grant substantially enhanced radial heat transport while preserving a well-established and relatively inexpensive multitubular reactor configuration. This offers unique potential for the intensification of many heat-transfer limited catalytic processes. A model-based comparative analysis of conductive honeycombs and open-cell foams versus conventional pellets as catalyst supports for the low-pressure methanol synthesis in packed-bed multitubular reactors (with Total, France) emphasized that structured catalysts enable compact reactors with shorter tubes, due to their flow-independent conductive heat transfer mechanism [5]

The second part of the webinar will introduce the two latest generations of conductive cellular substrates, i.e. open-cell foams (aka sponges) and 3D printed periodic open cellular structures (POCS), and report their recent application to the highly exothermic FTS and to the highly endothermic steam reforming of methane (MSR).

The intensification of Fischer-Tropsch fixed-bed reactors is gaining considerable attention in view of exploiting both associated and remote natural gas fields, as well as biomass, to produce clean liquid fuels, which requires scaling down the conventional packed-bed multitubular reactors to modular compact units, whose heat management is however highly critical. We have lately shown that heat exchange in FTS fixed-bed reactors is best enhanced by highly conductive internals based on Aluminium foams and even more by 3D printed POCS comprising an external skin, which maximizes the reactor wall tube/structure contact [6-7].

 

Figure 1. (a) radial and (b) external T-difference as a function of heat duty Q in FTS reactors loaded with Al packed-foam (green squares), packed-POCS (blue circles) and packed-POCS with skin (yellow triangles).

The increasing demand for distributed hydrogen production calls for downscaling also the traditional industrial methane steam reformers: we show that conductive structured catalysts enable higher thermal process efficiencies in compact externally heated reformers for MSR [8-9]. Further to that, in the last decade a substantial increase of electric energy production from renewable intermittent sources was observed. The large availability of relatively low-cost renewable electric energy represents a significant opportunity to decrease the carbon footprint of endothermic chemical processes. In particular, the application of this concept to the steam reforming of natural gas would provide a twofold beneficial effect in terms of reduced CO2 emissions and increased process efficiency. Preliminary results on the use of Joule heating for the MSR over washcoated SiC foams will be reported.

 

Figure 2. Reactor configurations and radial temperature profiles for fired packed bed, conductive packed foams and electrified packed foams in Methane Steam Reformers.

Acknowledgment
This project leading to the present results has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (GA no. 694910 /”INTENT”).
References
[1] E. Tronconi, G. Groppi, C.G. Visconti, Current Opinion in Chemical Engineering 5 (2014) 55-67.
[2] G. Groppi, E. Tronconi, C. Cortelli, R. Leanza, Ind.Eng.Chem. Res 51 (2012) 7590-7596.
[3] C.G. Visconti, E. Tronconi, L. Lietti, G. Groppi, P. Forzatti, C. Cristiani, R. Zennaro, S. Rossini, Appl. Catal. A: General 370 (2009) 93-101.
[4] C.G. Visconti, E. Tronconi, G. Groppi, L. Lietti, M. Iovane, S. Rossini, R. Zennaro, Chem. Eng. J. 171 (2011) 1294-1307.
[5] A. Montebelli, C.G. Visconti, G. Groppi, S. Kohler, H.J. Venvik, R. Myrstad, Appl. Catal. A: General 481 (2014) 96-103.
[6] L. Fratalocchi, C.G. Visconti, G. Groppi, L. Lietti, E. Tronconi, Chem. Eng. J. 349 (2018) 829-837
[7] L. Fratalocchi, G. Groppi, C. Visconti, L. Lietti, E. Tronconi, Chem. Eng. J. 386 (2020) 123988
[8] R. Balzarotti, A. Beretta, G. Groppi, E. Tronconi, Reaction Chemistry & Engineering, 4 (2019) 1387 – 1392
[9] R. Balzarotti, M. Ambrosetti, A. Beretta, G. Groppi, E. Tronconi, Chem. Eng. J., in press (2020).

 

Biography

Enrico Tronconi is a Professor of Chemical Engineering at the Department of Energy of Politecnico di Milano, Italy. He is the author of more than 260 refereed publications, inventor of 9 national and international granted patents, and has given more than 50 invited talks. His research interests concern the applications of Catalytic Reaction Engineering to environmental protection and to energy conversion. Enrico has investigated DeNOx aftertreatment technologies during the last twenty years in collaboration with major automotive Companies. He is also active in the study of novel structured catalysts and reactors for process intensification.

 

For Zoom information please contact dei-info@udel.edu

Details

Date:
June 5, 2020
Time:
9:00 am — 10:00 am